Neolithic man probably used fertilizers, but the first fertilizer produced by chemical processes was ordinary superphosphate, made early in the 19th century by treating bones with sulfuric acid. Coprolites and phosphate rock soon replaced bones as the P source. The K fertilizer industry started in Germany in 1861. In North America the K industry started during World War I and expanded with development of the New Mexico deposits in 1931 and the Saskatchewan deposits in 1958. Modern K fertilizers are more the product of physical than of chemical processes. The first synthetic N fertilizer was calcium nitrate, made in 1903 from nitric acid produced by the electric arc process. The availability of synthetic ammonia after 1913 led to many new N fertilizers, but physical quality was poor. In 1933 TVA was formed with a national responsibility to increase the efficiency of fertilizer manufacture and use. More than 75% of the fertilizer produced in the United States is made with processes developed by TVA.Major fertilizers and fertilizer intermediates introduced by TVA include ammonium nitrate, high‐analysis phosphates, diammonium phosphate, nitric phosphates, ammonium polyphosphate, urea ammonium phosphates, 11‐16‐0 and other liquid base solutions, superphosphoric acid, wet‐process superphosphoric acid, suspensions, granular urea, and S‐coated urea. These have had major impact upon the production of mixed fertilizers, bulk blending, and the fluid fertilizer industry. Future fertilizers not only must be technologically feasible, economical, and agronomically suitable—as have been past fertilizers—but also must meet various air and water pollution standards during production and have reduced total energy requirements.

No abstract

The potential of ammonia as a lower cost source of nitrogen was first realized in California in the early 1930s when ammonia gas was added to irrigation waters. Direct injection followed in 1939. Increased availability of ammonia gas after the Second World War provided the impetus to subsequent commercial development. The agronomic and economic implications of pressure and non-pressure systems and the practical significance of nitrogen source are discussed in detail.

No abstract

Synopsis Corn, cotton, and sorgo yields were increased while oats and clover yields were not affected by fumigation. The effect of fumigation was limited to the year of the treatment and nematode population built up rapidly after three months following treatment. Chemical composition of tissue was not significantly affected by nematode damage but total nutrient uptake expressed by the association of total growth and chemical composition was increased for those crops that responded to nematode control.